Planetary Transmission Layout for Nine-Speed Ratio Versatility
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Solution Overview
Problem
Current multi-speed transmissions face challenges in achieving a sufficient number of forward and reverse speed ratios efficiently, often requiring complex configurations of planetary gearsets and selective couplers that are not fully optimized for performance and versatility.
Innovation Solution
The use of a multi-speed transmission system incorporating four planetary gearsets and six selective couplers, including clutches and brakes, allows for the interconnection of components to achieve at least nine forward and one reverse speed ratio through specific engagement configurations, as illustrated in truth tables, enabling flexible torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gearsets and selective couplers are used to achieve multiple speed ratios, then the number of forward and reverse speed ratios increases, but the device complexity increases
Solution Approach 1:
The transmission system is divided into four distinct planetary gearsets (first, second, third, and fourth planetary gearsets), each with specific gear ratio characteristics. This segmentation allows independent control and engagement of different gearsets through selective couplers, enabling multiple speed ratios to be achieved by combining different gearsets in various configurations rather than using a single complex gear train.
Solution Approach 2:
Six selective couplers (first through sixth selective couplers) are employed to dynamically engage and disengage different planetary gearsets and interconnectors based on the desired speed ratio. This dynamic engagement allows the transmission to switch between different gear configurations (direct drive, reverse, various forward speeds) without mechanical reconfiguration, resolving the contradiction by providing adaptability through control rather than through fixed complex mechanics.
2Adaptability or versatility
If four planetary gearsets and six selective couplers are used to achieve at least nine forward and one reverse speed ratio, then the adaptability and versatility of the transmission system improve, but the device complexity increases
Solution Approach 1:
Each selective coupler is designed to perform multiple functions: the first selective coupler can engage the first planetary gearset for direct drive or first forward speed, the second selective coupler can engage the second planetary gearset for reverse or second forward speed, and so on. This multi-functionality allows a single coupler to control multiple operational modes, reducing the need for dedicated components for each function and thereby managing complexity while maintaining versatility.
Solution Approach 2:
Interconnectors are introduced as intermediary elements that link the planetary gearsets together in specific sequences. The interconnectors mediate the power flow between different gearsets, enabling complex gear combinations to be achieved through standardized connection interfaces. This intermediary approach simplifies the overall system architecture by providing modular connection points rather than requiring direct complex interlinking of all gearset components.
Data Source
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AI summary
A multi-speed transmission (100, 300, 500) including a plurality of planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314, 508, 510, 512, 514) and a plurality of selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372, 562, 564, 566, 568, 570, 572) to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314, 508, 510, 512, 514) may include a first planetary gearset (108, 308, 508), a second planetary gearset (110, 310, 510), a third planetary gearset (112, 312, 512), and a fourth planetary gearset (114, 314, 514). The plurality of selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372, 562, 564, 566, 568, 570, 572) may include a number of clutches (166, 168, 170, 172, 366, 368, 370, 372, 566, 568, 570, 572) and a number of brakes (162, 164, 362, 364, 562, 564). The multi-speed transmission (100, 300, 500) may have four planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314, 508, 510, 512, 514) and six selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372, 562, 564, 566, 568, 570, 572). The six selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372, 562, 564, 566, 568, 570, 572) may include four clutches (166, 168, 170, 172, 366, 368, 370, 372, 566, 568, 570, 572) and two brakes (162, 164, 362, 364, 562, 564).